Procedure that runs when the block is naturally generated

Basically I have done a single block feature that generates on cave ceillings in a custom dimension and I would like to block to run a procedure replaces the block and generates something else (in this case an ice stalagtite with random height) as soon as it is generated in the world. I've done already the custom block/"generator" block, the procedures and the feature so the block does generate but i've tried to do it with a "on update tick" procedure but naturally generated block don't tick unless you make them tick randomly (I don't want to do that as it would take a long time)

I know that it may not be possible but if someone has a solution (even a strange one) I would be sooo glad